/*
 * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
 * The software in this package is published under the terms of the CPAL v1.0
 * license, a copy of which has been included with this distribution in the
 * LICENSE.txt file.
 */
package org.mule.runtime.core.util.counters.impl;

import org.mule.runtime.core.util.counters.CounterFactory.Type;

public class TimeAverage extends AggregateCounter {

  private double sum = 0.0;
  private double lastValue = 0.0;
  private final long firstTime = System.currentTimeMillis();
  private long lastTime = firstTime;

  public TimeAverage(String name, AbstractCounter base) {
    super(name, Type.AVERAGE, base);
  }

  @Override
  public double nextValue() {
    long current = System.currentTimeMillis();
    return (sum + lastValue * (current - this.lastTime)) / (current - firstTime);
  }

  @Override
  public void doCompute() {
    long current = System.currentTimeMillis();
    this.sum += this.lastValue * (current - this.lastTime);
    this.lastValue = getBase().nextValue();
    this.lastTime = current;
  }
}
